Telemetric device



H. H. JOHNSON TELEMETRIC DEVICE Filed March 26, 1945 @HEEJI ,E l

, G HEH [il l Jan. 1s, 1949.

Patented Jan. 18, 1949 UNITEDr STATES PATENT OFFICE TELEMETRIC DEVICE Henry H. Johnson, Glendale, Calif.

Application March 2.6, 1946, serial No. 657,309

5 claims. (01177-351) This invention relates generally to telemetric devices, and particularly to telemetric -devices for translating as an electrical quantity a displacement of a mechanical device.

Itis an object of the invention to provide devices for translating displacement of a mechanical member into voltages.

Itis a further-object of the invention to provide a device for translating a mechanical rectilinear motion into a corresponding electrical potential. 1

Itis another object of the invention to provide a device for translating a mechanical rotary motion into a corresponding electrical potential.

Another object of the invention resides in the ,provision oi devices of the above character which are operable directly from a 60 cycle voltage supply whereby to simplify the construction and mode of operation of such devices.

' It is another object of my invention to provide a device ofthe above characterwhich shall operate by changing the reluctance of a magnetic flux path associated with a power input and a voltage output coil, respectively. Y I Another object of the invention resides in the provision of a tel'emetric device of the above character of simple construction, whereby to render the device economical to build and substantiall free of maintenance difculties.

The above and still further objects-and advantages of my invention will become obvious upon study of the following detailed speciiication 'when taken in conjunction with the accompanying drawings, wherein: I

Figure 1 is an elevational view of oneembodimentfof my invention;

Figure 2 is an end view corresponding to Figure l;

`Figureis a'plan View of va second-embodiment of my invention; and

Figure 4 is a vertical sectional view taken on the line 4-'4'of Figure 3.

Referring now to the drawings in detail, and particularly to Figure 1 thereof, reference numeral yI designates a steel angle iron comprising the main frame for my device, and having secured to a vertical kface 2 thereof by means of bolts 3 a further angle iron 4, which may be machined or bent to conformto various desired geometrical shapes, if desired. In particular, the angle iron 4 may be positioned with respect to the bed 5 of the angle iron, at a slight angle thereto, and may be rectilinear, for the particular purpose which I presently have in mind.

Bolted to an edge of the angle iron I by means of bolts t may be a transparent plastic plate '1 having an inwardly extending lip i8. A like lip 9, parallel to the lip 8, and which may be of metal, if desired, is secured to the face 2 of the angle iron I, the lips 8 and yil together with the bed 5 comprising a runway for a translatable member I0, which may be moved along the said runway by means of an actuating rod II, the memberk I0 being constrained to move in slidable relation to the bed 5 by means cfa pair of bent spring members l2, secured as by rivets or screws I5 to laterally extending arms I3 and I4 which may be secured to or form part of the member ID. The arms I3 and I4 extend under the lips 3 and 9 and are spaced therefrom, .and the spring members I2 engage the lips 8 and 9 to spring bias the under surface ofthe arms I3 and I4 into firm engagement with the bed 5.

The structure heretofore described being largely constructed of magnetic material, and in viewof the continuously varying character of the spacing between the bed 5 of the member I `and the under face of the angle iron 4, a path of varying reluctance is provided between the member I0 and the under face of the angle iron 4, the reluctance of said path being dependent upon the position of the member I0 longitudinally of the angle iron I.

A eld or power input coil I6 may be wound on the member I0, to which may be supplied alterhating current of any desired frequency and voltage, but which for vpurposes of convenience may 'be Sil cycles at IIIl volts. An output or pick-up coil I'I may be wound on the member I0, either concentric' with the coil I6 or in any other desired relation thereto. In such case the voltage induced in the coil II by variation of current in the coil I6 will vary in accordance with the reluctance across the airgap between the member Ill and the under face of the angle iron 4, and since that reluctance depends upon the longitudinal position of the member I0 as determined by displacements of the rod II, the said output voltage is a lineaiiunction of the said displacements.

A series of graduations I8 may be provided in the outer lface of the plastic angle member I, and an index line I9 provided in the face of the varm I 4 'whereby the position of the member I0 may be determined, as desired.

t will be Obvious that voltages developed atthe output terminals 20 of the coil I1 may be amplified, if desired, and in any event may be extended to remote locations in a manner well known per se, and there utilized for remote indication of the location or displacement of the member I0, or for Icontrol of motive devices to move apparatus of any -desired character to positions in correspondence with successive positions taken by the member i0.

Referring now to Figures 3 and 4 of the drawings, the numeral 30 represents a lcasing constructed of magnetic material, and which, while of cylindrical shape externally, comprises an internal generally cylindrical wall 3l tapering in a volute curve from a maximum radius at the point 32 to a minimum radius at the point 33, in a smoothly graduated manner, the change of radius per degree of circumference remaining constant throughout.

A cylindrical boss 34 centrally located internally of the casing 30, comprises axially thereof a hole machined to provide -a bearing for the rotatable shaft 35, which carries a radius arm 36, the boss 34, the shaft 35 and the arm 36 being constructed of magnetic material, wholly or in part, whereby to provide a magnetic circuit for the flux lines produced by a magnet coil 31 which surrounds the boss 34 and which comprises a pair of leads 38 extending externally of the casing 30.

The leads 38 may be connected to a source of alternating current, which may be that usually commercially available, for purposes of convenience, the ilux lines responsive to current in the coil v31 being constrained to ilow through the arm 36, across 'an air-gap 33 extending between an end 39 of the arm 36 and through the wall of the casing 30, whereby a ilux path of different reluc-tance is provided for each possible position of the arm 36,` or of the shaft 35.

Wound about the arm 36 is a pick-up coil 40, the terminals of which are connected to brushes 4|, supported by an ear 46 riding on a pair of sliprings 42 secured to the boss 34, voltage being available from the slip-rings 42 by means of a further pair of output leads 44 connected to the rings 42 and extending externally of the Icasing 30 via an aperture 45 in the boss 34.

It will be apparent that the position of the shaft 35 will, in accordance with the embodiment of my invention illustrated in Figures 3 and 4 of the drawings, be represented by the magnitude of an output voltage at the leads 44, due to the variations in magnetic flux linking with the coil 40 in its various possible positions, and that such voltage may ybe utilized telemetrically or for positional control of apparatus of various types, in the same manner as the output voltage of the coil I'I of Figure l.

While I have described two specific embodiments of my invention, it will be understood that variations of the structural details thereof, as well as of the arrangement of parts, may be resorted to Without violating the spirit of the invention as defined by the appended claims.

What I claim and desire to secure by Letters Patent of the United States is:

1. In a telemetric device, a support of magnetic material having a bottom ange, a top plate of magnetic material attached to said support which is almost parallel to but slopes gradually in a longitudinal direction with respect to the bottom flange, a magnetic member movable between said bottom flange and said top plate, and a pair Si coils mounted on said movable magnetic mem- 2. In a telemetric device, a support of magnetic material having a bottom flange, .a top plate of magnetic material secured to said support which is almost parallel to but slopes gradually in a longitudinal direction with respect to the bottom ange, a magnetic member of inverted T shape movable between said top plate and said bottom flange and having its base slidable along said bottom ange, and a pair of coils carried by the stem of said T shaped magnetic member.

3.. In a telemetric device, a support of magnetic material having a bottomilange, a top plate of l magnetic material secured to said support which is almost parallel :to but slopes gradually in a longitudinal direction with respect to the bottom ange, a magnetic member of inverted T shape movably mounted below said top plate and along said bot-tom flange, a lip formed on said support and overlying the base of said inverted T shaped member, a plate over the -outer face of said bottom ange and also having a lip overlying the Abase of said inverted T shaped member, and a. pair of coils carried by the stem of said T shaped member.

4. In a telemetric device, a support of magnetic material having a bottom ange, a top plate of magnetic material secured to said support which is almost parallel to but slopes gradually in a longitudinal direction with respect to said bottom ange, a magnetic member of inverted T shape movable under said -top plate and along said bottom flange, a lip formed on said support overlying `the base of said inverted T shaped member, a plate over the outer face of said bottom flange and also having a lip overlying the base of said inverted T shaped member, half elliptical springs secured to said base and abutting said overlying lips, and a pair of coils mounted on the stem of said T shaped member.

5. In a telemetric device, a support of magnetic material having a bottom flange, a top plate of magnetic material secured to said support which is almost parallel to but slopes` gradually in a longitudinal direction with respect to said bottom iiange, a magnetic member of inverted T shape mounted under said top plate and slidable along said bottom flange, a lip formed on said support overlying the base of said inverted T shaped member, a plate over the outer face of said bottom flange and also having a lip overlying the base of said inverted T shaped member, a rod member secured to said inverted T shaped member for shifting same longitudinally under said top plate and along said bottom flange, and a pair of coils mounted on the stem of the inverted T shaped member. HENRY H. JOHNSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date Re. 18,889 Sams July 4, 1933 1,921,983 Wittkuhns Aug. 3, 1933 2,340,609 Mestas Feb. 1, 1944 FOREIGN PATENTS Number Country Date 330,914 Great Britain June 12, 1930 473,563 Great Britain Oct. 15, 1937 

